land subsidence

Land subsidence is an environmental phenomenon of the gradual or sudden subsidence of the land. The purpose of the present study is to evaluate the land subsidence in Shabestar plain of East Azerbaijan province. Using Small Baseline Subset (SBAS) time series analysis method, the crust surface displacement rate between 2018 and 2021 is investigated. The maximum subsidence is seen in the southern and southeastern parts of the plain with a maximum rate of about 8 cm per year in the direction of the satellite line of sight. Also, using AHP the conditioning factors are weighted and the land subsidence susceptibility (LSS) is modeled using spatial analyses. Thereupon, Shabstar plain was classified into five regions with the LSS: "Very High": 3%, "High": 20%, "Moderate": 25%, "Low": 33% and "Very Low": 19% of the total area of the plain. To verify the accuracy of the subsidence susceptibility model, the displacement map obtained from radar interferometry was utilized, the area under the ROC curve of 86% confirmed the good prediction accuracy of the model. Also, the model was assessed by performing sensitivity analysis for most important conditioning factors. The introduced model can provide useful and reliable information for managers and decision-makers of the region for the effective and timely 'prevention' and 'mitigation' planning with low cost and time.

Land subsidence refers to the vertical and downward movement of the earth's surface. This phenomenon may occur naturally or as a result of human activities. It causes damages to communication networks, infrastructure, and structures and agricultural land. In the past few years, land subsidence has occurred as a crisis in many of plains in Iran and has raised significant concerns. In this study, Shabestar Plain, one of the high-risk plains of East Azarbaijan Province, was selected as the study area. In order to identify the land subsidence susceptibility at different locations and also to identify the factors that influence land subsidence, random forest algorithm is used. In this study, a land subsidence map used as the inventory map, prepared by using time series based SAR interferometry technique as training data. The results confirmed that the southern part of the study area has very high susceptibility to land subsidence. In the modeling of land subsidence susceptibility by random forest, 5.63 % of the study area had Very High susceptibility and 6.37% had High land subsidence susceptibility. Also, based on random forest modeling, the highest effect was related to "elevation", "groundwater level", and "land use", and the least effect among the factors involved was related to "distance from fault". Finally the model was evaluated using area under Receiver Operating Characteristic curve, AUC= 96% confirmed very good predictive power of the model. The results of this paper can be used for planning for the development of various constructions and land uses in the future. Also, considering the possibility to identify regions and facilities at risk, timely and appropriate actions can be taken for prevention and minimizing financial and human losses.

The environmental consequences of land subsidence are destructive, costly and irreparable, and include creating cracks on the surface of the earth, damaging human structures such as building foundations, streets, bridges, roads, and power transmission lines. Sewage is destruction of irrigation systems and fertile agricultural soils and damage to ancient sites. Remote sensing methods, unlike mapping data and topographical maps, which are in physical contact with terrestrial phenomena, are without the slightest interference on terrestrial phenomena, and measuring and evaluating changes in phenomena are evaluated from a distance. Short receiving time and high spatial accuracy of radar images have made it used as a general and widely used tool to estimate land subsidence. According to the statistics announced in the country of Iran, the adverse effects caused by land subsidence are not a low number and are rapidly developing and spreading in different regions of the country. Leave irreparable damage. Ardabil plain, with its rich underground water resources and good soil, has always been of interest in the last half century and has been a suitable place for providing drinking water and agriculture. With the boom of agriculture from the 1960s onwards and as a result the excessive harvest from the aforementioned table since 1363, the aforementioned source began to decline and the continuation of this situation in the following years caused this plain to become more critical.

In order to carry out this research, the data of 22 piezometric wells in the Ardabil plain have been used. The time period used in this research is a 7-year period from 1395 to 1402. The method used for the data of this section is the BRF method, as one of the methods of radial functions, which is used due to its low error value and high accuracy. SAR images of the European Space Agency's Sentinel 1 satellite in SLC format and with vv polarization have been used to find out the changes in land subsidence in the Ardabil plain. The images used by the Sentinel 1 satellite (in c-band with a wavelength of 5.6 cm) are in the group of sensors with medium resolution in terms of spatial resolution. The radar interferometry method provides the possibility of producing a digital model of the ground height, whose optimal height accuracy for c-band data with a wavelength of 5.6 cm is about 5 meters. This method is able to reveal surface changes in the ground in different intervals with millimeter accuracy by using at least 2 or more radar images. In this method, an artificial interferogram is produced with the help of digital elevation model of the earth and conversion of height into phase, and in this way, with the help of reverse DEM data, the phase effect caused by topography is calculated and removed from the phase difference values. The remaining phase difference belongs to the effect of surface displacement and atmosphere.

The results of the investigation of piezometric wells in the area of Ardabil Plain show that the maximum drop in the underground water level is 48.77 meters in the southeast of Ardabil Plain and the lowest drop in the underground water level is 1.57 meters in the north. Eastern Ardabil plain was calculated. The amount of fluctuations in the water level of piezometric wells shows that the highest amount of fluctuations was in the area of Pirqavam wells, Arallovi Bozor and Khalil Abad lands. The lowest fluctuation was also observed in the area of Agchechai wells, Nojedeh. In the studied time period, the water level of Khalilabad piezometric well in 2015 was 2.96 meters, while in 1402, the water level in this area reached 46.3 meters. During 7 years, the water level has dropped by 43 meters, which indicates a critical situation in this sector. The lowest fluctuation of the water level is also for the Aghche-chai well. The land subsidence map of Ardabil plain shows that: the south-eastern parts of Ardabil city and also to some extent in the southern part have suffered ground subsidence due to the extraction of underground water. In the next order, the western parts of Ardabil city are prone to land subsidence. Based on this map, the maximum amount of ground subsidence has been calculated at around 598 mm in the area of Khalil Abad well. In the area of Khalil Abad well, the situation of underground water level drop is very critical and it has dropped by 43 meters during 7 years from 1395 to 1402. The overlapping results of the underground water level and co-depth curves with the results of radar interferometry show the accuracy of the findings in this section. Overlapping the location of the historical sites with the land subsidence map shows that, first of all, Tapraqlu hill (first millennium BC) is in the area of land subsidence with a rate of 250 mm.

The results of the application of this method revealed a very high level of land subsidence for the Ardabil plain (598 mm during a 7-year period). The southeastern areas of Ardabil plain have found a critical situation in recent years due to unprincipled exploitation and lack of proper management. Overlapping the location of the historical sites with the land subsidence map showed that Taparaglu hill with a rate of 250 mm and Ozrik Tepe-si with a rate of 69 mm are in the area of land subsidence, respectively. The three historic sites of Qala-Bovini, Niar Tepesi and Tezre Tepesi are also located in the area prone to land subsidence with rates of 27 mm, 46 mm and 49 mm, respectively. The cause of land subsidence in the Ardabil plain, according to the studies conducted on the changes in the underground water level, is the excessive exploitation of the underground water resources for the cultivation of agricultural products and providing the possibility of compaction of the underlying layers. In general, it can be said that the research results indicate the involvement of historical sites in the area of land subsidence.

Land subsidence is a global geological hazard resulting from human activities and natural factors, requiring thorough investigation in many countries, including Iran, the United States, the United Kingdom, Australia, China, Egypt, France, Germany, India, Italy, Japan, Mexico, Poland, Saudi Arabia, Sweden, and the Netherlands. Iran is one of the most hazardous regions globally, experiencing numerous hazards each year. One of the risks that occurs due to climate change and population growth in plains is land subsidence. Reports indicate that 50% of Iran's plains (300 plains) are at risk of subsidence, causing significant problems for agricultural, residential, and transportation areas. While the consequences of land subsidence may not be as apparent as earthquakes or floods, its long-term and heightened impacts are more significant.In recent years, attention has been given to land subsidence in Iran, with numerous studies published on this topic. A preliminary review of the conducted research reveals their dispersion and lack of consistency. The importance of land subsidence and the abundance of scattered studies in this field prompted the authors to provide a systematic review of these studies. The systematic review approach aims to organize and integrate research findings from various studies in a specific domain to present new insights. Therefore, the main objective of this study is to comprehensively analyze the status of land subsidence in Iran using a systematic review approach. The systematic review approach is a research method that explores and extensively analyzes available resources in the studied field, providing reliable results.

The aim of the present study is to provide a comprehensive analysis of the status of land subsidence in Iran. To achieve this objective, a systematic review was conducted to assess the state of land subsidence in Iran. Systematic review is an essential tool for presenting evidence in a rigorous and reliable manner, making it suitable for gaining a comprehensive understanding of land subsidence. The literature for this study was selected based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) framework. PRISMA is a validated method for guiding systematic reviews of academic literature.

The rate of land subsidence varies in different provinces and time periods. For example, in Azarshahr, it is 2.1 centimeters per year, in Marand plain, it is 2 centimeters per year, in Salmas plain, it is 11 centimeters in 2019, in Ardabil plain, it is 4.4 centimeters per year, in Meshkin Shahr plain, it is 9.35 centimeters per year, in Khorramdarreh, it is 4 centimeters per year, in Abhar, it is 4.3 centimeters per year, in Qorveh plain, the average is 11 centimeters per year, and in Mahidasht, it is 3 centimeters per year.The systematic review of research findings indicates that the subsidence rate in Tehran ranges from 3 to 43 centimeters. Additionally, subsidence rates of 11 to 27 centimeters have been reported in Shahriar and 20 centimeters in Varamin. In Ghorveh, the subsidence rate is 6.28 centimeters per year, in Dindarlu, it is 30 centimeters per year, in Marvdasht, it is 5.2 centimeters per year, in Noorabad, it is 4 centimeters per year, in Jiroft, it is 12 centimeters per year, in Kerman, it is 6 centimeters, and in Minab, it is 13 centimeters per year. In Mahyar plain, the subsidence rate ranges from a minimum of 4.6 to a maximum of 2.8 centimeters per year, in Najafabad, it is 7.7 centimeters per year, in Abarkuh, the range is from 5.5 to 12 centimeters per year, and in Dezful, it is 9.5 centimeters peryear. In Jooyin plain, the subsidence rate is 4.6 centimeters per year, in Sabzevar, it is 2 centimeters per year, in Mashhad, the range is from 14 to 23 centimeters per year, in Neyshabur, it is 10 centimeters per year, in Gorgan, it is approximately 5 centimeters per year, in Semnan, it ranges from 10 to 13 centimeters per year, and in Eyvanki, it is 11 centimeters per year. In Hashtgerd plain, the subsidence rate is 7.4 centimeters per year, in Qazvin, it is 3 centimeters per year, in Qom, it is 3 centimeters per year, in Aliabad, it is 16 centimeters per year, and in Shazand, it is 6 centimeters per year.

Salmas Plain is one of the important agricultural regions of West Azerbaijan province, playing a significant role in the region's agriculture and development. In recent decades, the plain has been severely impacted by the phenomenon of subsidence due to the over-extraction of groundwater from aquifers. Therefore, identifying areas prone to subsidence in the Salmas Plain is of particular importance for the management and control of this phenomenon. In this study, a fuzzy neural inference system model was used to predict subsidence-prone areas. To achieve this goal, seven important factors contributing to subsidence in the region were analyzed: land slope, digital elevation model, vegetation, groundwater depth, distance from roads, distance from rivers, and distance from piezometric wells. The information related to these factors was collected in ArcGIS software and transferred to MATLAB software for model implementation. Using the C-fold CV method, the data were randomly divided into three groups: 70% for training, 20% for testing, and 10% for validation. These data were introduced to MATLAB for training, testing, and validation. The data were accurately trained and validated, achieving a precision of 10⁻⁸. Several different membership functions, including trapezoidal, triangular, Gaussian, two-sided Gaussian, and bell curve functions, were tested in the model. The results showed that the trapezoidalmembership function, with a regression correlation coefficient of 0.86, and the Gaussian membership function, with a regression correlation coefficient of 0.81, performed best in identifying areas prone to subsidence.Based on the results, the eastern areas and the outlet of the plain have experienced significant drops in groundwater levels and subsidence. Statistical studies also revealed that groundwater levels have dropped by over 18 meters, averaging1.23 meters per year in recent years. The crisis has been exacerbated over the past two decades by over-extraction of groundwater for agriculture, combined with a storage-to-recharge ratio of 0.03% and unfavorable climatic conditions.The spatial pattern of land subsidence in Iran indicates that this phenomenon is strongly linked to the uncontrolled abstraction of groundwater resources, driven by increasing urban water consumption and low agricultural water efficiency. Drought conditions and excessive groundwater withdrawal have not only affected arid and central regions of the country but have also extended to semi-arid and humid areas in the northwest. Geological experts have reported that 300 out of 600 plains in the country are affected by subsidence. Due to the importance of this issue, many researchers have studied land subsidence. Their results indicate that the Salmas Plain, as part of the Lake Urmia catchment area, is experiencing a major subsidence crisis. This crisis has caused significant problems for infrastructure in many parts of the Salmas Plain, especially in the Qara Gheshlagh region. The main cause of subsidence is the over-extraction of water from wells constructed for agricultural purposes, which has led to a steady decline in the volume of aquifers.

To evaluate the susceptibility of the Salmas Plain to subsidence, the required data and statistics up to 2019 (1398 in the Iranian calendar) were collected as follows:Digital topographic maps (1:25,000 scale), a digital geological map (1:100,000 scale) of Salmas city, and thematic maps (e.g., slope, land use, geology, distance from wells, groundwater depth, distance from rivers, and distance from faults).GPS data, meteorological information, soil maps, and aerial photographs (1:20,000 scale).Digital Elevation Model (DEM) with a resolution of 30 x 30 meters.In this study, seven criteria were analyzed: vegetation type, groundwater depth, distance from roads, distance from rivers, distance from piezometric wells, digital elevation model, and slope. All criteria were first standardized in ArcGIS software and converted into an 800 x 800-meter grid. The data from each grid were then compiled into a matrix and transferred to MATLAB for analysis using the Adaptive Neuro-Fuzzy Inference System (ANFIS) model.To ensure accurate modeling, the satellite data were divided into three parts: 70% for training, 20% for testing, and 10% for validation. This process ensured precise measurement of modeling accuracy and error rates using MATLAB software.

Studies revealed that over the past 41 years, groundwater levels in the Salmas Plain have dropped by 18 meters, averaging 1.23 meters per year from 2014 to 2015 (93-94 in the Iranian calendar). The plain, characterized by clay and silty layers, has experienced significant aquifer compression and reduced porosity due to over-extraction of groundwater. This has resulted in land subsidence across the study area.The model results demonstrated that trapezoidal and triangular membership functions performed best, achieving error coefficients of 10⁻⁷ and 10⁻⁸, with mean error rates of 0.18 and 0.20, respectively. The regression correlation coefficients were 0.86 and 0.80, confirming the model's accuracy in identifying areas of high subsidence sensitivity. Approximately 8.9 and 6.3 square kilometers of the plain were classified as very high-risk areas, while 1.8 and 3.2 square kilometerswere classified as high-risk zones. These findings indicate that the proposed model can effectively predict subsidence with high accuracy and reliability.Furthermore, the results highlight that over-extraction of groundwater has caused aquifer compaction and subsidence. Linear regression analysis confirmed the model's accuracy, with a correlation coefficient of 0.86.

The Salmas Plain is a vital agricultural region where groundwater serves as the primary water source. Over 70% of extracted groundwater is used for agriculture. Irregular groundwater extraction and reduced rainfall have significantly lowered groundwater levels, exacerbating subsidence in the plain. Since 1993, the annual water table drop has increased to 1.23 meters.The fuzzy neural inference system model demonstrated that trapezoidal and triangular membership functions with regression correlations of 0.86 and 0.81 provided reliable results, predicting subsidence-prone areas effectively. The findings suggest that 8.6% and 6.3% of the study area are at very high risk of subsidence. Immediate measures are required to control groundwater extraction and manage the subsidence crisis in the Salmas Plain.

The deficiency of surface water in arid and semi-arid territories has exacerbated the dependence on groundwater resources, resulting in considerable reductions in groundwater levels. This phenomenon has been particularly pronounced in numerous plains throughout Iran, where the diminution has exacerbated issues related to land subsidence. A comprehensive understanding of groundwater level variations is imperative for enhancing water management strategies and alleviating the associated hazards. A range of statistical, mathematical, and machine-learning methodologies have been utilized to model the dynamics of groundwater aquifers. Recently, deep neural network algorithms have gained prominence in the investigation of surface and groundwater resources, particularly in light of the spatiotemporal characteristics inherent to groundwater. In the present investigation, a hybrid spatiotemporal data mining framework, denoted as Wavelet-PCA, was employed to analyze data acquired from 44 piezometric wells situated in the Qahavand plain over a span of three decades (1988-2018) for the purpose of elucidating temporal and spatial patterns associated with fluctuations in groundwater levels. Subsequently, a sophisticated deep recurrent neural network architecture incorporating Long Short-Term Memory (LSTM) was implemented to model the time series data resulting from the data mining procedure. Various degrees of wavelet transformation were applied to effectively capture the intricate trends in groundwater levels. The LSTM model exhibited a coefficient of determination (R²) of 0.85 for the training dataset while achieving an R² of 0.62 for the testing dataset. The research additionally examined regional patterns of land subsidence utilizing radar interferometry data obtained from the Sentinel-1 satellite during the period from 2014 to 2019. The results revealed an average maximum subsidence measurement of 9 centimeters, with the most pronounced subsidence noted in regions that are undergoing the most substantial declines in groundwater levels. This observed relationship between groundwater depletion and land subsidence underscores the necessity for judicious land use planning and the implementation of effective water resource management strategies in analogous regions.

The Persepolis World Heritage Site, located in the northern part of Fars Province, is one of Iran’s most significant historical landmarks, dating back to the Achaemenid period (300–560 BC). Studies have shown that the surrounding areas are experiencing land subsidence due to prolonged drought, dam construction, and excessive groundwater extraction. Therefore, this study aims to investigate and map the stability/instability patterns of Persepolis from October 27, 2016, to February 22, 2020, using radar interferometry. To analyze the time series of subsidence in the study area, we applied Persepolis Time Series Analysis (PS-InSAR). The analysis was based on 180 SENTINEL-1A images, covering both ascending and descending orbits, to assess the rate of land deformation at the Persepolis archaeological site. Specifically, we focused on the Takht-e Jamshid region, located on the southern slope of Mount Ko Rahmat, and identified and measured land deformation phenomena there. Our results show that Takht-e Jamshid has not experienced significant subsidence during the observation period (2016–2020), with an estimated rate of -5 to -10 mm per year. This study provides evidence that the observed deformation at the site is not related to the subsidence of the Marvdasht aquifers, which are underlain by Quaternary sediments. These findings contribute to a deeper understanding of land subsidence dynamics in the Takht-e Jamshid region and underscore the need for continued monitoring and management of this invaluable archaeological site.

Land subsidence is a significant hazard affecting many plains of Iran, including the Eyvanakey Plain in Semnan Province. The Eyvanakey Plain has a high potential for subsidence due to the influence of climate and topography. Given the importance of this issue, the present research aims to evaluate land subsidence in the Eyvanakey Plain and analyze the factors contributing to its occurrence.In this study, Sentinel-1 radar images, Landsat satellite imagery, and data from piezometric wells in the region were utilized as primary research data. The key tools employed include GMT, ArcGIS, ENVI, and SPSS software. The study was conducted in two main phases: first, an assessment of land subsidence in the region from 2016 to 2022, and second, an analysis of the impact of groundwater depletion and land use changes on subsidence.The results indicate that the study area experienced subsidence ranging from 28 to 533 mm over the six-year period, which is a significant amount. Spatial analysis of the subsidence reveals that the highest rates occurred in the southern parts of the Eyvanakey Plain. These areas also experienced an annual drop in groundwater levels of approximately 2 meters, highlighting groundwater depletion as one of the primary causes of subsidence.Furthermore, based on the results, the extent of man-made areas and agricultural lands increased by 6.9 km² and 2.7 km², respectively, between 1992 and 2022. Given that the highest levels of subsidence were observed in these land use areas, the development of agricultural lands and man-made areas has been identified as the main cause of subsidence.

Land subsidence is a phenomenon emerging in most of the alluvial plains of Iran in the last few decades due to the gradual or sudden lowering of the land surface. It is prompted by various factors such as over-harvesting of underground water, tectonic activities, mining, etc. Neyshabur Plain is not an exception to this rule and due to the over-exploitation of underground water in the last few decades, the water level of the aquifer has dropped and the hydrostatic pressure has declined. This has led to subsidence, which has affected rural and urban areas. This plain covers an area of 3477 square kilometers, of which an area of 591 square kilometers, which is home to a population of 59,000 people and 179 villages, struggles with severe land subsidence. In this research, the relationship between the aquifer and underground water level and its compatibility with the areas facing subsidence is investigated. Research shows that for every 83-cm decline in  groundwater level, there is on average 10.5 cm subsidence in the surface of Neyshabur Plain. In this research, sentinel satellite images from October 2014 to December 2017 taken by the Mapping Organization have been used by radar interferometric method. The results suggest that the indiscriminate exploitation of underground water resources has triggered land subsidence and cracks in rural areas, especially in the periphery of the villages of Firuzeh, Abu Saadi, Birum Abad, Faiz Abad, Sarab Koushak, Urdughash, and Farrakhk which are in some cases as big as 15 to 20 cm per year. The highest and the lowest subsidence, i.e., 1 cm per year, is reported in the villages of Dasht, Mehdi Abad, and Khoresofla.

Investigation and monitoring of displacement field due to deformations of the earth's surface is one of the most important and applied studies in various topics such as geology, geomorphology, geophysical. Land subsidence is one of the destructive geological phenomena that can cause irreparable financial and life losses. In fact, subsidence is a morphological phenomenon that in the logical state of this phenomenon includes collapse or downward sitting of the earth's surface, which can also have a small horizontal displacement vector (Solari et al., 2018). This phenomenon has been charted as a serious crisis in most plains of the country in recent years. Therefore, identifying and reducing the consequences of subsidence phenomenon requires a monitoring system. Several methods have been proposed to accurately evaluate and measure this phenomenon, which radar interferometry technique was introduced as one of the methods of radar image processing in active remote sensing, a useful tool in monitoring the placements of the earth's surface (Sadeghi et al., 2012).So that over the past several years, the use of radar interferometry technique to evaluate and monitor land subsidence has increased and its time series algorithms such as PSI and SBAS have provided the possibility of measuring ground displacements (Abu pit et al., 2010). Therefore, in this study, we tried to estimate the time series of kermanshah plain subsidence during 2016-2021 using Sentinel 1 satellite imagery and using radar interferometry technique under small baseline length approach.

Radar interferometry with artificial valve is a remote sensing technique. In which two or more radar images are used to produce digital elevation models or to map the displacement of the earth's surface. In this technique, the phase difference between two different waves is measured and this phase difference is attributed to the change in distance between the sensor and the ground target or the displacement of the earth's surface. Ideally, each interferogram should have only a phase difference caused by the displacement of the earth. For this reason, other components must be removed or deducted so that the remaining phase can be obtained only from displacement. In the above article, using radar data and using radar interferometry technique and small baseline time series analysis, the time series of land subsidence phenomenon in Kermanshah plain is monitored and measured. In this method, only visual couples are used that the vertical component of the baseline is less than the critical value of the baseline. Also, their time baseline is minimized at the same time. In this way, only interferences are formed that have good quality. Then, the results of this method, which is the average annual subsidence map in the desired period, are investigated to explain the relationship between the cause of subsidence occurring on the plain surface with changes in groundwater level and the thickness of fine sediments.

In order to investigate the behavior pattern of the earth surface in the long term, we used time series analysis using small baseline method. To do this, among multiple images and interferograms, 36 radar images were selected from sentinel 1 sensor at the time interval of 2016 (June) to 2021 (January) and selected by the lowest baseline of 88 interferograms that had a suitable spatial and temporal baseline and were dispersed in the interferometry process. After obtaining the interferogram images, the noises in the mapping interference must be removed so that the residual noise is only due to the displacements of the earth's surface, resulting in the average map of the earth's surface displacements in the desired timeframe. Evaluation of the obtained map indicates maximum subsidence of -100 mm/year in the western parts of the plain. Then, by preparing a map of water level drop in the plain, the relationship between these two variables was investigated, which did not show a significant correlation between them, so by examining another effective factor in the plain surface, we realized that in addition to the drop in the water level, the thickness of fine sediments should also be considered because by summing these two factors together, the surface subsidence. The earth intensifies. This is well known in the western parts of the plain

The maximum subsidence calculated between 2016 and 2021 is 10 cm, which covers an area of about 1.67% of the total area. Then, in order to explain the cause of subsidence occurring in the region, we investigated the relationship between groundwater level drop and subsidence in the region. By evaluating 54 piezometer wells in the plain, it has been observed that the maximum subsidence range is not in accordance with the maximum drop in water level. Therefore, we were looking for another effective factor in the plain surface that by studying the thickness of fine sediments (clay and silt) in the maximum subsidence range, we saw a high thickness of fine sediments which has experienced a moderate drop from the water surface about 5 meters per year. Therefore, it is not always possible to see the linear relationship between water level drop and land subsidence.investigation of steady state index showthebarchan dunes, with annual displacement rate more than 12 meters,have the maximum number and highest rates of displacement, and have the lowest steady state. Thus this group is demanding the more attention and planning requirements for stabilization of quicksand and environmental management of mobile barchan dunes.

The phenomenon of land subsidence is one of the dangers that has occurred in many areas of the plains of our country in recent years and has led to many problems. Identifying areas subject to land subsidence and estimating its rate has an important role in managing and controlling this phenomenon. The radar interferometry technique is a powerful tool in estimation and has the amount of ground subsidence with an accuracy in the millimeter range using phase observations. In this research, the data of Sentinel 1A satellite from 2017 to 2021 have been used in order to monitor the subsidence that happened in Chenaran city by sensor-radar interference method. To investigate the subsidence of Chenaran city, radar interferometric method, Sentinel 1 satellite images and available information of piezometric wells in the area were used and the piezometric changes of the water level of the wells were analyzed. According to the results of the current research, the amount of land subsidence for each period is 9 cm for 2017-2018, 10 cm for 2018-2019, 10 cm for 2020-2019, and 13 cm for 2020-2021. be Also, the results of the radar interferometric technique showed that during the statistical period, 42 cm of subsidence occurred in the studied area. In addition, the areas with severe land subsidence, especially in the areas of Seyed Abad, Akhlamed, Haji Abad, Chahcheh, Hashem Abad, Kalate Sheikha, etc., corresponded to the areas with the highest level of underground water level drop. In general, the most important and main cause of land subsidence in the studied area is the excessive extraction of underground water resources, which has caused the dangers of land subsidence.

Groundwater depletion is one of the scenarios of climate change, which has become a global crisis today. Land use changes and land cover and rapid urbanization are the main causes. The decline of groundwater in recent years has caused land subsidence in many alluvial plains of the country. Uncontrolled and uncontrolled consumption of surface and groundwater resources, reduction of precipitation, concentration of consumption in some places (Imbalance between demand and water supply potential), inadequate cultivation pattern and lack of proper irrigation and digging of multiple wells and operation Irregularity of them in recent decades has caused a critical situation of groundwater resources in most plains of the country. To Groundwater level in most of the country's aquifers is constantly declining and the average annual decline over It has been 12 meters for the last 15 years. Decreasing the groundwater level of the plains increases the cost of water extraction and Increased energy consumption, reduced water quality and the emergence of land subsidence. As side effects, with decreasing volume The phenomenon of subsidence occurs in different spatial and temporal situations with different characteristics such as groundwater content, morphology, pedology and geology, which have different destructive effects. Shabestar-Sufian plain is one of the plains in the northwest of the country, which is facing many restrictions in terms of access to surface water and groundwater and is in a critical situation. In recent decades, the increasing trend of irrigated agricultural lands and overexploitation of groundwater resources has put the plain at risk of subsidence. Groundwater level drop is one of the most common causes of subsidence. Recognizing and examining ways to control it and prevent accelerating the process and expansion of subsidence phenomenon prevents the occurrence of hazards such as groundwater pollution, land slope change, well wall collapse, gradual sinking of masts and structures, changing the slope of rivers and roads Be. Risks that cause significant financial and human losses and on the other hand cause a waste of time and manpower, and pollution and destruction of the environment. In Shabestar-Sufian plain, there may be signs of subsidence in the form of sloping pipes, piping, shallow cavities, which is a warning for this fertile plain. If proper planning is not done regarding the exploitation of groundwater, we will soon see the destruction of lands, houses, water pollution, etc. In this regard,. The aim of this study was to identify areas prone to subsidence, for which the Fuzzy-AHP model was used. Information layers including land slope, altitude, geomorphological units, distance from the river, land use, lithology, groundwater level decline have been used as effective criteria. Expert Choice software was used to perform the calculations and after obtaining the final weights of each criterion, the obtained weight was applied on the layers according to the expert opinions in GIS software. Also, for the fuzzy model, fuzzy maps were combined using the fuzzy gamma operator. To modulate the very high sensitivity of the multiplication fuzzy operator and also the very low sensitivity of the sum fuzzy, the gamma fuzzy operator has been used and finally a map of subsidence prone areas has been prepared. Landslide risk areas are classified into five categories: very low (10.8%), low (14.2%), medium (7.22%), high (7.28%) and very high (2.23%). have became. About 52% of the southern, middle and western regions of the region are at very high risk of landslides due to excessive use of groundwater. In terms of spatial distribution, the highest risk of land subsidence is in the villages of Aq Kahriz, Dizaj Khalil, Shanglabad, Bagherabad, Kafi Malek, Kushk, Hallaji, Yousefabad, Ali Biglou, Haftcheshmeh and Qom Tappeh. Complete and common data were used between 2001 and 2017. Water loss map was prepared by idw interpolation method in gis environment. The results of groundwater status assessments in the region indicate that the study area in recent years has been faced with an increasing trend of groundwater level decline, so that the rate of water level decline has reached 4.7 meters in 18 years, a sharp drop in land subsidence in this region Has caused. . The calculated results are confirmed by examining the time series of water level drop in the wells of the region. Analysis of geomorphological parameters of the region has also shown that the same occurrence of subsidence has been in areas with a slope between zero to 5 valleys, have experienced less subsidence in the slope of more than 5 degrees or no subsidence has occurred in these slopes at all. It has a high subsidence in places with a height of less than 1500 meters, and with salt cover and alluvial materials, as well as areas with agricultural use. Areas close to the river were less prone to subsidence. Flat and smooth slope directions have been the main area of occurrence of this phenomenon. It can be concluded from the results that more than half of the 5% (51%) of the study are prone to high to very high subsidence, this means the critical situation in this plain.

Land subsidence is one of the dangers that have occurred in many parts of the world, especially in Iran, in recent years is the dangers caused by land subsidence. The most important cause of it is the illegal extraction of underground water sources and like other environmental hazards, it has created many problems and problems for the government's agricultural, civil, economic-social affairs. The city of Neishabur is located on the level of the Neishabur plain, which is one of the most important plains of Khorasan-Razavi province, which is facing the crisis of land subsidence. The radar interferometric technique is a powerful tool with millimeter accuracy in estimating subsidence using phase observations. In this research, the Sentinel 1A satellite data from 2017 to 2022 have been used in order to monitor the amount of subsidence that occurred in the area of Neishabur city, which is a small part of Neishabur plain. The results of radar interferometry showed that 18 cm of subsidence occurred in the studied area during the statistical period. In addition, to find out the cause of the subsidence, the information of piezometric wells in the area was collected and their changes during the period of 1370-1398 were examined. The amount of subsidence recorded for each period is 4 cm for 2017-2018 (1395-1396), 6 cm for 2018-2019 (1396-1397), 5 cm for 2019-2020 (1397-1398) and 2 cm. It was obtained for the period of 2020-2021 (1398-1399) and 1 cm for the period of 2021-2022 (1399-1400). In addition, the results of the research showed that there is a close relationship between the drop in the underground water level and areas with land subsidence in the area of Neishabur city.

The phenomenon of land subsidence depends on many factors of geological phenomena, slow movements of the crust and the outflow of lava, human activities and draining of aquifers, land subsidence in agricultural lands in the plains causes the destruction of irrigation systems and the destruction of fertile soils. It will be accompanied by cracking and making the land unusable. The main problem of land subsidence is the irreversibility of the land. Persistent subsidence in the plains occurs as a result of indiscriminate extraction of groundwater and drainage of aquifers, which leads to compaction of clay layers. Iran is one of the countries that is facing the crisis of underground water resources in recent years, droughts, construction of dams, on the one hand, the increase in population, the need for water resources, excessive drilling of illegal wells, and the cultivation of aquatic species on the other hand. It caused the danger of water crisis in this country. The purpose of this research is to investigate the cultivation pattern and its role on the subsidence of Noorabad aquifer in Fars province.Currently, extensive cultivation of rice is carried out in this province and consumes water resources. From a long time ago, due to the rich surface water resources of the Bovan, Kati, Doregzan, and Marwarid rivers, as well as the suitable climate, farmers used to dedicate their lands to the cultivation of rice and safijat, and the passage of time and the reduction of surface resources Deep wells have continued the same flooding method as in the past and these species are still used as the dominant species in the region. The conditions have changed, but the cultivation is still in the old way, and this is one of the main problems that has doubled the subsidence crisis in the region as an important issue. Among the objectives of this research is to identify the types of water cultivation in the aquifer area, the areas with maximum subsidence and its relationship with the water types. One of the main innovations in this research is to investigate the relationship between the cultivation pattern and land subsidence for the first time. Is.Modifying the cultivation pattern is an important solution to prevent the progress of land subsidence by developing the cultivation of medicinal plants and transferring cultivation from open space to greenhouse space and developing planting and changing the time of cultivation from spring to autumn is a way to deal with water shortage. Actions such as pressurized irrigation and laser leveling and the implementation of protective vessels and the development of drought-tolerant gardens and the development of greenhouse cultivation along with training farmers to adapt to water shortages, modifying the cultivation pattern and preventing excessive extraction of underground resources are important measures. in reducing the effects of subsidence phenomenonThe method used in this research is analytical in order to prepare the cultivation pattern in the target area using Centil 2 images in the three months of the summer of 2021 in the GEE environment and it was prepared and then sampled using the support vector machine model in the ENVI software environment. (ROI) of the selected species was done in order to calculate the amount of subsidence using the radar interferometric method in the SNAP software environment.Investigating the amount of land subsidence in cultivated species shows that all cultivated species in the Noorabad aquifer are considered water-bearing and do not correspond to the conditions of the region. Rice cultivation is one of the most critical species in the Noorabad basin. Due to the high consumption of water and waterlogging and the high use of underground water resources, this species causes the drop of underground water and land subsidence. According to the graph, it shows that the amount of land subsidence in rice species has reached the maximum amount of about 10 centimeters per year. This situation is indicative of excessive wastage of underground water reserves and land subsidence in the Noorabad watershed. Sifijat is ranked second with a 3 cm settlement. These conditions indicate the crisis of subsidence in the region's aquifer.Land subsidence is a widespread phenomenon in the world, which has had significant quantitative and qualitative manifestations in the last few decades, mainly due to the excessive exploitation of underground water resources and the intensification of its level drop. The results of the study of land subsidence showed that several factors are effective in the occurrence of land subsidence. Therefore, the greatest impact on land subsidence is related to rice cultivation, which has the highest water demand in the summer season. Cultivation in a period of 1 year shows that rice has the highest rate with -10 cm of sediment per year, followed by safijat, with -3 cm. In these areas, due to meeting the water needs of residential communities, including the city of Noorabad and the surrounding areas, as well as meeting the water needs of agricultural activities, there is more water resource exploitation, and the extraction of underground water is very high. The factors with the intervention of the dry climate of this region have caused the high talent of these regions in the discussion of subsidence, and it has been identified as one of the critical areas of the city in the subsidence map. The results of radar interferometry show that the indiscriminate harvesting of underground reserves has caused the subsidence of the central part of the aquifer, including summer rice and corn, at the level of the danger zone of land subsidence, which has increased by 5 cm. The results obtained from the cultivation pattern and its relationship with land subsidence show a positive correlation of R2 coefficient equal to 98% and the lowest error rate is about 0.001

Due to the specific geographical and geological situation of Iran, the earthquake phenomenon imposes numerous human and financial losses on our country every year, and identifying areas prone to earthquakes and providing practical solutions are among the ways to reduce these losses. Also, by examining the impact of the subsidence phenomenon in the seismic process and reaching a comprehensive and practical model, it is possible to prevent and adjust the volume and scope of potential incidents rooted from this widespread hazard; noting that the relevant institutions have all the necessary regulations and standards for construction and safety regarding this process. The earthquake-prone areas which were subject to subsidence and earthquakes at the same time were reviewed. Conducting comprehensive and detailed studies in order to create a complete and scientific structure to identify and provide maps and updated information on the adaptation of the seismic situation and the subsidence of the country helps to prevent the occurrence of accidents and widespread loss of life and capital during these phenomena. In this regard, this study was planned aiming to investigate and assess the effect of subsidence on the seismicity trends of Varamin and Shahriar plains in Tehran region.

The current research aims to investigate the effect of subsidence rate changes on the seismicity trend using Sentinel-1 satellite data from 2014 to 2021. The studied area is in the southern part of the Alborz mountain range, namely Varamin Plain and Shahriar Plain which are located in the southern and western extremes of Tehran province, respectively. Due to the sensitivity of the research topic and to obtain more accurate results, a combination of digital information and hydrological data along with radar images of the area and field data were processed and analysed. Geological maps 1:50000, fault and seismicity 1:1000000 from the Geological Organization, topography 1:25000 from the National Mapping Organization, and seismic data from the years 1350 to 1400 were obtained from the Geophysics Institute of Tehran University and the International Research Institute of Seismology and Earthquake Engineering of Tehran. The data from 46 piezometer wells in the region from 2014 to 2021 were used for zoning and checking the underground water level. The satellite data of the Sentinel-1 sensor was used for interferometry to determine the subsidence rate of the region.

In the present study, the correction of the seismic catalog with standard techniques and the micro-seismic catalog showed that Varamin and Shahriar plains have subsidence rates of 65 and 54.5 cm per year, respectively, based on changes of 600,000 cubic meters per year in the volume of the aquifer. The studied case has led to the minimum stress changes in the area to the extent of 5 bar to 17 bar (equivalent to 500 to 1700 kilopascals). Also, the seismicity pattern of the area shows an increasing trend in the occurrence of subsequent earthquakes on one side, and a shortening of the seismic return period in the studied area on the other side.

The high consistency of the data trend in the distribution charts demonstrates the consistency of the subsidence trend and, subsequently, its effect on the seismicity trend of the studied area, which in turn indicates the effect of subsidence on the seismicity trend in the studied areas. The stress output resulting from loading shows a high increase in the stress of the area on one hand, and a decrease in pore pressure on the other hand. This is due to the decrease in the resistance of the soil in the studied area which manifests in the form of collapses and falling of structures and, with an emphasis on the extensive decrease in the strength of surface and subsurface layers, causes subsidence and intensification of subsidence in the region. To put it shortly, both of these phenomena will influence one another in an increasing cycle.

The studied area is located as a part of the Caspian Sea catchment with an area of ​​about 50083 hectares in the east of Kurdistan province, northwest of Iran. In this research, the data of 34 observation wells were used to investigate the condition of the underground water level and its depth fluctuations, and also to investigate the phenomenon of subsidence in region 8, the Sentinel-1 satellite image was used in the period (2014-2021). The research method includes statistical analysis of changes in the underground water level and interferometry of radar image. The results of the research showed that in the years 2014 to 2021, Dehgolan plain has subsided by -12 to -32 cm. In this way, an average of 6 centimeters of subsidence has occurred annually in these areas. The complete subsidence pattern of Dehgolan plain and the analysis of profiles and water level maps showed the center-west and southwest trends and the maximum subsidence is related to the central and western parts. Therefore, the conformity of the subsidence areas and the curves of the water table level drop, the use of underground water resources indicates that the withdrawal of more than the amount of aquifer nutrition has caused an increase in the effective stress in the sediments because the subsidence areas coincide with the areas of the groundwater level drop, or are located near them. In other words, this location adaptation in the high plains of Dehgolan shows that the cause of the subsidence of the high plains is the drop in the groundwater level, and as a result, the high plains are more vulnerable to the risk of subsidence.

Various natural phenomena have had a significant impact on the quality of human life since long ago. One of these types of natural phenomena is the deformation and displacement of the earth's surface, including subsidence. Subsidence is a morphological phenomenon that occurs under the influence of the downward movement of the earth. The salient features of radar images and the acceptable accuracy of the radar interferometric method have provided a powerful tool for researchers in investigating land subsidence. For this reason, 35 radar images of the Sentinel 1 sensor in the ascending orbit and transit 174 in the period from 2016 (June) to 2021 (January) were used to investigate the land subsidence in the Kermanshah plain. To analyze the time series of these images to prepare the average annual subsidence map in the plain, the radar interferometric technique was used under PSI and SBAS approaches. The results show the maximum land subsidence of 100 mm in the SBAS method and 10 mm in the PSI method in the west and northwest of the plain for 6 years. Finally, the maximum range was investigated in terms of geology and geo-hydrology. The results of the investigations showed that the land use of the maximum land subsidence area includes irrigated and rainfed agricultural lands, with the highest amount of water withdrawal in the agricultural sector, along with an average drop in the water level of 8 meters in 20 years in wells with a large thickness of fine-grained sediments. Is. In general, land subsidence in the area is affected by human and natural factors

Land subsidence is one of the environmental hazards caused by various factors, and especially in recent years, it has caused a lot of damage to human societies. The Khanmirza plain aquifer has also faced this phenomenon in recent years. The creation of wide gaps and cracks on the surface of the plain and the release of gas from them makes the issue of subsidence important. For this reason, the present study tries to monitor and measure the amount of land subsidence in Khanmirza plain, and evaluate and analyze its relationship with the withdrawal of excess from underground water sources. For this purpose, in order to investigate the changes in the underground water level during 10 years and in two different time frames from the IDW geostatistics model and to estimate the subsidence of the land surface using the differential radar interferometric method and from the Sentinel-1A radar images during 5 years and in Three different time periods were used. The results of the research indicate that displacement of the earth's surface in different time periods is different and does not have a constant trend, while the trend of the drop of the underground water level has been increasing in the whole time period. Accordingly, according to the results of the research, there is no significant relationship between the indiscriminate extraction of underground water sources and the subsidence areas in Khanmirza plain.

The occurrence of land subsidence phenomenon and its potential hazards in the plains of Iran due to the water crisis and drought period has grown significantly in recent years. In this study, the zoning of land subsidence hazard in the Hashtgerd plain was discussed and 19 criteria were selected as factors that influence the subsidence. The mentioned layers were prepared in GIS, weighted based on the best-worst method (BWM) and integrated using the Weighted Overlay Index (WOI). The results of BWM method showed that groundwater abstraction (0.219), the type of geological formation (0.157), the decrease of groundwater level (0.079), and groundwater depth (0.078) are important factors on the potential of subsidence hazard in the study area. Moreover, in order to evaluate the results of this model, the ROC curve was used, which has an accuracy of 90%. The results showed that land subsidence hazard of 10.66% of the study area was in very low category, 38.51% in low category, 31.49% in medium category, 11.66% in high category and 7.69% is in the very high category. According to the results, there are areas with a high probability of subsidence in the central part of Hashtgerd Plain, which requires continuous evaluation, controling, and monitoring of the criteria that affect the situation.

One of the dangers in many areas in recent years is subsidence. Landslides are less harmful than other hazards and its adverse consequences will directly affect human, industrial, agricultural, and civil development. The importance of paying attention to this issue is that the most harmful side effects are irreparable. Scientometric research have provided a comprehensive understanding of global research on the subject. Data were obtained from the Scopus Scientific Database (1965-2022). Most of the scientific research on land subsidence has been on the United States and China. The most important aggravating factors for the occurrence of hazards include the exploitation of groundwater and mineral extraction, which has been emphasized in most studies. On the other hand, the use of scientific technologies over the past years has become more widespread in landslide research. Now it is used more to predict the risk. Most research on the risk of land subsidence has focused on the use of methods and models, but its impacts on different aspects of human life have not been considered. The results of this research can help reduce and manage the negative consequences of land subsidence.